Clipboard Guard

About

Some websites read your clipboard without asking. If you've copied a password, address, or anything private, that data can be silently accessed by page scripts the moment you visit the site. Clipboard Guard stops this.

The extension injects a protective script before any page JavaScript runs, intercepting clipboard read attempts at the API level. When a site tries to access your clipboard via navigator.clipboard.readText() or navigator.clipboard.read(), Clipboard Guard blocks it and shows a toast notification so you know exactly what happened.

You can Allow Once for a single read, or Always Allow to whitelist a trusted domain. Manage your whitelist from the popup at any time — add or remove sites with one click.

An activity log shows every blocked and allowed clipboard access attempt with timestamps, so you have full visibility into which sites are trying to read your data. A red badge on the extension icon counts how many attempts have been blocked today.

FEATURES
- Real-time clipboard read interception (navigator.clipboard.readText and .read)
- Toast notification on every blocked attempt
- Allow Once / Always Allow options per site
- Whitelist management in the popup
- Activity log of all blocked and allowed attempts
- Daily badge counter for blocked reads
- Enable/disable toggle
- Works on all sites including dynamically loaded content

HOW IT WORKS
Clipboard Guard uses two content scripts:
1. A MAIN world script that overrides clipboard read APIs before any page JavaScript executes
2. An ISOLATED world script that handles the UI (toast notifications, whitelist checks) and communicates with the background service worker

The extension never reads your clipboard contents. It only intercepts the API call and blocks or allows the request.

PRIVACY
- No data leaves your browser
- No external servers or network requests
- The extension never reads or stores clipboard contents
- Only stores: whitelist domains, event log (last 50 entries), enable/disable preference
- Built on Manifest V3

By Patrick Bushe · bushe.co